Injection devices and systems and methods for using them

ABSTRACT

Systems and methods are provided for injecting one or more agents into tissue within a patient&#39;s body. In one embodiment, an injection device is provided that includes an outer tubular member comprising a proximal end, a distal end sized for introduction into a patient&#39;s body, and a lumen extending between the proximal and distal ends; a relatively small cross-section needle tip extending distally beyond the distal end,; and an internal pressure release member slidably disposed within the lumen between a distal position and a proximal position to prevent viscous injectate from expressing from the distal tip.

RELATED APPLICATION DATA

This application claims benefit of co-pending provisional applicationsSer. No. 62/563,826, filed Sep. 27, 2017, the entire disclosure of whichis expressly incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to apparatus, systems, andmethods for performing medical procedures, and more particularly toneedles or other injection devices, and to systems and methods forinjecting one or more agents into tissue, e.g., viscous injectates, intotissue, e.g., within a patient's heart or other location, using suchinjection devices.

BACKGROUND

While injection devices and needle systems have been in use for manyyears, recent developments in minimally invasive procedures requireneedle systems capable of accessing distant or difficult to accessregions of the body, capable of delivering agents of high viscosity(e.g., chemo-embolization agents, depot drug formulations, fillers,etc.), capable of delivering agents with low shear (cells), and/orcapable of delivering agents at high flow rates.

Injection devices may include a simple needle attached to a syringe, aneedle assembly designed to pass through the working channel of anendoscope or catheter or other minimally invasive introduction device,and/or a needle incorporated into a more complicated device. In suchcases, injecting viscous fluids into a body cavity, space, or tissueinvolves a number of unique challenges compared to injecting non-viscousfluids. These challenges/problems include, among others, efficientmovement of the fluid with minimized pressure requirement and/or shearforce, clog prevention, clog elimination/clearing, multiple sequentialinjections, injection of one or more additional, in some cases lessviscous, fluids sequentially or intermittently without significant crosscontamination, etc.

Further, the need for flexible catheter-based needle injection systemshas increased in recent years given the proliferation of potentialinjectable materials (e.g., stem cells, ablative agents,chemotherapeutic agents, bio-polymers, other pharmaceuticals, etc.). Thebenefits of these materials frequently depend on the ability toprecisely target their delivery to specific anatomical locations, whichdepends on many common catheter challenges most especially flexibility.Additionally, in the case of viscous fluids or high volume injections,the need arises for a design to balance two conflicting objectives—asmall needle to minimize trauma, etc. and a large diameter to enableease of injection, e.g., to maximize or permit adequate flow at areasonable pressure, e.g., which can be easily generated by a handheldsyringe.

In addition, due to the viscous nature of some injectates, the highpressure required to inject may not immediately be released from theneedle or injection system upon removal of injection pressures.Additionally, the “static friction” of viscous injectates in the needleand needle body may be such that a full vacuum (e.g., −14.7 psi) doesnot move the injectate and, hence, the application of vacuum may not besufficient to release the built-up high pressure inside the needle orover the full length of the injection device. Finally, because there isa capacitance/expansion/compression to the system (both in theinjectate, which may have air or other gas bubbles suspended ordissolved therein, and/or otherwise compressible, and the needle, needlebody, and/or injection path), the built-up high pressure may cause aslow but unacceptable expression of injectate over an extended period oftime, e.g., two to eight (2-8) minutes, e.g., between multipleinjections, which may result in the injectate being exposed within thepatient's vasculature or other undesired location within the patient'sbody.

Therefore, apparatus and methods that facilitate injection of viscousmaterials would be useful.

SUMMARY

The present invention is directed to apparatus, systems, and methods forperforming minimally invasive medical procedures. More particularly, thepresent invention is directed to needles or other injection devices, andto systems and methods for injecting one or more agents into tissue,e.g., viscous injectates into tissue, e.g., within a patient's heart orother location, using such injection devices.

In accordance with one embodiment, a device is provided for injecting aviscous injectate into tissue within a patient's body that includes atubular outer member comprising a proximal end, a distal end sized forintroduction into a patient's body, and a lumen extending between theproximal and distal ends; a needle or other tubular extension extendingdistally beyond the distal end to a distal tip, the tubular extensionhaving a cross-section smaller than the distal end and a passagecommunicating between the lumen and an outlet in the distal tip; and aninner pressure release member slidably disposed within the lumen betweena distal position and a proximal position to prevent the injectate fromexpressing from the distal tip after delivery at a target location.

Optionally, the device may also include a manifold coupled to theproximal end including a source of injectable material and an actuatorfor selectively directing the injectable material from the sourcethrough the lumen and out the outlet. In one embodiment, a proximal endof the pressure release member may extend from the proximal end of theouter member such that the pressure release member may be manuallyretracted from the distal position, during delivery of the injectate, tothe proximal position, after delivery of the injectate, e.g., to releasepressure and/or remove residual injectate from the passage.

In accordance with another embodiment, a system is provided forinjecting a viscous injectate into tissue within a patient's body thatincludes an outer member comprising a proximal end, a distal end sizedfor introduction into a patient's body, and a lumen extending betweenthe proximal and distal ends; a needle tip extending distally beyond thedistal end to a distal tip and including a passage communicating betweenthe lumen and an outlet in the distal tip; a source of viscous injectatecoupled to the proximal end and communicating with the lumen fordelivering the injectate through the lumen and passage and out theoutlet; and an inner member slidably disposed within the lumen, theinner member comprising a proximal end disposed adjacent the outermember proximal end and a distal end disposed within the lumen, theinner member having an outer profile smaller than inner profile of thelumen such that the injectate passes through the lumen around the innermember, the inner member movable from a distal position wherein theinner member distal end is disposed adjacent the passage during deliveryof the injectate and a proximal position in which the inner memberdistal end is directed proximally away from the passage after deliveryof the injectate to prevent the injectate from expressing from thedistal tip.

In accordance with yet another embodiment, a method is provided forinjecting one or more agents into tissue, e.g., into tissue within apatient's heart and/or other location, using an injection deviceincluding an outer member including a proximal end, a distal end, and alumen extending therebetween a, needle tip extending from the distalend, and a pressure release member slidably disposed within the lumen.The distal end of the outer member may be introduced into a body lumenadjacent a target injection site, the needle tip may be inserted intotissue at the target injection site, and, with a distal end of thepressure release member disposed adjacent the needle tip, injectate maybe delivered from a source through the lumen around the pressure releasemember and through the needle tip into the tissue. After delivering theinjectate, the pressure release member may be withdrawn proximally suchthat the pressure release member distal end moves proximally away fromthe passage to prevent injectate from expressing out the needle tip.

Other aspects and features of the present invention will become apparentfrom consideration of the following description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate exemplary embodiments of the invention, inwhich:

FIG. 1 is a side view of an exemplary embodiment of an injection deviceincluding an outer tubular member terminating in a low profile needletip and an internal pressure release member slidably disposed within thetubular member.

FIG. 2 is a cross-sectional detail of the injection device of FIG. 1showing the pressure release member in an initial distal positionadjacent the needle tip.

FIG. 3 is a cross-section detail of the injection device of FIG. 1showing the pressure release member in a proximal position to preventexpression of viscous injectate from the needle tip.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Turning to the drawings, FIG. 1 shows an exemplary embodiment of aneedle or injection device 8 for performing a medical procedure within apatient's body, e.g., for injecting one or more agents into tissue,e.g., into the wall of a patient's heart (not shown). For example, thedevice 8 may be used to deliver viscous fluids, gels, agents, and/orother flowable materials, e.g., including one or more diagnostic and/ortherapeutic compounds (generally referred to herein as “injectates”).

As shown, the injection device 8 generally includes an outer shaft ortubular member 10 including a proximal end or portion 12, a distal endor portion 14 sized for introduction into a patient's body, one or morelumens, e.g., lumen 18, extending between the proximal and distal ends12, 14, a relatively low profile distal extension or needle tip 20, andan inner release member 30. In addition, the device 8 may include amanifold or handle 50 coupled to the proximal end 12, e.g., includingone or more ports 52 and/or actuators (not shown), and a source ofinjectate 60. Optionally, one or more additional components or devicesmay be provided, e.g., an access or delivery sheath, endoscope, one ormore stylets, and/or one or more guidewires or rails (not shown) toprovide a system for performing a procedure, as described elsewhereherein.

Generally, the outer shaft 10 is an elongate tubular member defining acentral longitudinal axis 16 extending between the proximal and distalends 12, 14, and one or more lumens 18 extending between the proximaland distal ends 12, 14. In the embodiment shown in FIG. 1, the outershaft 10 may include a single lumen 18 formed by the wall of the shaft10. Alternatively, the shaft 10 may include one or more additionallumens within the wall of the shaft 10 (not shown), if desired, or theshaft 10 may be formed as one or more separate tubular members, e.g.,bladders or sleeves (also not shown), within an outer coil or tubularshaft, e.g., similar to those described in U.S. Publication No.2017/0119956, the entire disclosure of which is expressly incorporatedby reference herein. For example, in one alternative, the outer shaft 18may include a secondary lumen (not shown) that may be used to delivercontrast or other fluids out the needle tip 20.

The outer shaft 10 may be substantially flexible, semi-rigid, and/orrigid along its length, and may be formed from a variety of materials,including plastic, metal, and/or composite materials, as is well knownto those skilled in the art. In addition, the shaft 10 may have asubstantially uniform outer diameter (or other cross-section) betweenthe proximal and distal ends 12, 14, or the diameter may vary along thelength of the shaft 10.

For example, in one embodiment, the shaft 10 may have a substantiallyuniform construction and size along its length between the proximal anddistal ends 12, 14. Alternatively, a distal portion of the shaft 10,e.g., having a length of about ninety centimeters (90 cm) or more,immediately adjacent to or spaced a predetermined distance from theneedle tip 20, may be substantially flexible to facilitate advancementthrough tortuous anatomy, while a proximal region, e.g., extending apredetermined distance from the proximal end 12, e.g. about thirtycentimeters (30 cm) or more, may be semi-rigid or rigid to enhancepushability and/or torqueability of the outer shaft 10 withoutsubstantial risk of buckling or kinking. Optionally, the lumen 18 mayinclude lubricious material or may be formed from one or more layers ofthermoplastic or other polymeric material including one or more coatingson the inner surface thereof having desired properties, e.g., ahydrophilic and/or lubricious coating, e.g., similar to the linersdisclosed in U.S. Pat. Nos. 7,550,053 and 7,553,387, and U.S.Publication No. 2009/0126862, the disclosures of which are expresslyincorporated by reference herein.

Optionally, a distal stop (not shown) may be provided on the distal end14 of the outer shaft 10, and the needle tip 20 may extend from thedistal stop. In an exemplary embodiment, the distal stop may be abulbous, rounded, and/or other atraumatically shaped element coupled tothe distal end 14 of the outer shaft 10. The tissue stop may have adiameter or other cross-section that is larger than the distal end 14and/or may include a rounded or substantially flat distal surface thatis substantially larger in surface area than the cross-section of theneedle tip 20, e.g., to provide tactile feedback when the needle tip 20is inserted into tissue and/or limit insertion of the needle tip 20 intotissue.

In addition or alternatively, the shaft 10 may include one or morefeatures to enhance visibility under ultrasound, Mill or other imagingmodalities, e.g., by providing one or more radiopaque markers on and/ordoping one or more regions adjacent the needle tip 20, e.g. as known inthe art. For example, one or more radiopaque markers (not shown) may beprovided, e.g., at the base of the needle tip 20, on the distal end 14,and/or on the distal stop, to facilitate identification of the needletip 20 and/or depth of penetration into tissue.

The needle tip 20 may be coupled to and/or otherwise extend distallyfrom the distal end 14 of the shaft 12 (or the distal stop), e.g., suchthat the shaft 12 defines a main portion of the device 10 and the needletip 20 defines a smaller penetrating portion. In one embodiment, theneedle tip 20 may be a single tubular body having a first end 22 coupledto the distal end 14 of the shaft 12, and a second end 24 terminating ina distal tip 25 having a beveled, multi-faceted grind, trocar grind, orother sharpened shape, as desired to facilitate penetration into tissue.A passage or lumen 26 may extend from the first end 22 to one or moreoutlets, e.g., outlet 27, in the distal tip 25. In addition oralternatively, one or more outlets may be provided along the outersurface of the needle tip 20, e.g., adjacent to or instead of the outlet27. In addition or alternatively, the needle tip 20 may be substantiallystraight, e.g., as shown in FIG. 1, or may be formed in a fixed curvedor other curvilinear shape, e.g., to facilitate securement and/oraccessing tissue not directly aligned with the longitudinal axis 16.

In an exemplary embodiment, the needle tip 20 may be formed from asection of hypotube or other uniform tubular body, similar toconventional needles e.g., formed from metal, such as stainless steel,plastic, or composite material, having desired mechanical properties,e.g., sufficient column strength to allow the needle tip 20 to bedirected into tissue by manipulating the shaft 10 from the proximal end12. In exemplary embodiments, the needle tip 20 may have a relativelythin wall, e.g., no larger than 25 gauge, or no larger than 32 gauge, toreduce the rigidity of the needle tip 64, if desired. The proximal end22 of the needle tip 20 may be attached to the distal end 14 of theshaft 10, e.g., by one or more of interference fit, cooperatingconnectors, bonding with adhesive, fusing, welding, soldering, and thelike, e.g., such that the needle tip 20 is centered on the distal end 14and extends substantially parallel to the longitudinal axis 16.Alternatively, the distal extension 20 may be coupled to a separatemanifold or other connector (not shown), e.g., an enlarged distal stop(not shown), which may include one or more internal chambers or passagescommunicating between the lumen 18 and the passage 26, e.g., similar tothe devices described in U.S. Publication No. 2017/0119956.

Optionally, a tapered or flared transition (not shown) may be providedat the first end 22 of the needle tip 20 to facilitate connection to thedistal end 14 of the shaft 10. Alternatively, a blunt transition may beprovided if desired, e.g., to provide a stop, which may provide tactilefeedback or otherwise prevent directing the needle tip 20 too deep intotissue.

Thus, in an exemplary embodiment, the entire outer shaft 10 or at leastthe distal end 14 of the outer shaft 10 may have a first outer diameterand the needle tip 20 may have a second outer diameter that is smallerthan the first outer diameter. In exemplary embodiments, the first outerdiameter may be between about 0.040-0.080 inch (1.0-2.0 mm) and thesecond outer diameter may be between about 0.010-0.025 inch(0.025-0.0625 mm), e.g., about ten to fifty percent (10-50%) smallerthan the first outer diameter. Similarly, the outer shaft 10 may have afirst length between the first and second ends 12, 14 that issubstantially longer than a second length of the needle tip 20, e.g.,such that the shaft 10 may extend from an access site, e.g., apercutaneous access site in the patient's skin through the patient'svasculature to a target treatment site, e.g., a chamber within thepatient's heart. In exemplary embodiments, the first length may bebetween about forty and one hundred forty centimeters (40-140 cm) andthe second length may be between about two and fifteen millimeters (2-15mm), e.g., not more than about five millimeters (5 mm).

One potential advantage of having the outer shaft 10 larger than thedistal extension 20 is that the lumen 18 of the device 8 may have arelatively larger diameter along most of the length of the device 8,e.g., along the entire length of the outer shaft 10 if the outer shaft10 has a substantially uniform diameter between the proximal and distalends 12, 14. For example, if a single lumen 18 is provided in the outershaft 10, the inner diameter of the lumen 18 may be maximized, which mayreduce friction for materials passing through the lumen 18, which may beparticularly useful for viscous fluids or to reduce shear on fluidspassing through the lumen 18. The passage 26 through the needle tip 20may have a diameter substantially smaller than the lumen 18 but, givenits relatively short length, may add minimal resistance to deliver suchfluids. Thus, with the resistance to flow lower within the lumen 18 ofthe outer shaft 10 than within the passage 26 of the needle tip 20, theoverall force needed to deliver the fluids may be reduced, as comparedto a uniform diameter lumen sized similar to the passage 26.

With additional reference to FIGS. 2 and 3, the inner release member 30generally is an elongate solid or hollow wire or other elongate memberslidably disposed within the lumen and including a proximal end 32 and adistal end 34. The inner member 30 may have a substantially uniformdiameter along its length or may, alternatively, comprise a variablediameter, e.g. a relatively smaller proximal diameter (e.g., to reduceresistance to fluid flow) and a relatively larger distal diameter (e.g.,to achieve greater volume displacement and release of pressure with lessaxial translation).

In addition or alternatively, the inner member 30 may include arelatively uniform stiffness along its length. Alternatively, the innermember 30 may include variable stiffness along its length, e.g., arelatively stiffer proximal segment (e.g., to achieve greaterpushability) and a relatively more flexible distal segment (e.g., toavoid damaging the lumen 18 or outer shaft 10 when passing throughand/or to impart greater flexibility to the distal end 14).

The inner member 30 may pass through the lumen 18 relativelyconcentrically. Alternatively, the inner member 30 may be positionedaway from the central axis of the lumen 18, e.g., in the event thatthere are one or more other elements passing through the lumen 18, suchas an accessory infusion lumen.

Optionally, the inner member 30 may include and inflatable element (notshown), which may be subsequently be deflated after injection, e.g., tocause volume displacement distally with the lumen 18. For example, theinner member 30 may include a relatively small diameter tubular proximalelement have an inner lumen for passage of inflation fluid and adistally positioned inflatable element (not shown), e.g., a balloon onthe distal end 34. The inner member 30 may contain a fluid, e.g., air,nitrogen, saline, and the like, that is relatively less viscous than theinjectate passing through the lumen 18. During injection of theinjectate, the inflatable element (not shown) may be inflated andsubsequently deflated, e.g., passively or under vacuum, to cause avolume displacement and pressure release distally within the lumen 18.

The inner member 30 may have sufficient length that the proximal end 32extends from or is disposed within the handle 50 and the distal end 34is disposed adjacent the passage 26. The inner member 30 may have anouter diameter or other cross-section that is smaller than the innerdiameter of the lumen 18 such that injectate may be delivered throughthe lumen around the inner member 30. In an exemplary embodiment, theinner member 30 may have an outer diameter of not more than 0.014 inch(0.35 mm) and the lumen 18 may have an inner diameter of at least about0.022 inch (0.55 mm) to provide sufficient clearance that viscousmaterials may be delivered through the lumen 18 around the inner member30.

The inner member 30 may be slidably disposed within the outer shaft 10between a distal position where the distal end 34 is disposedimmediately proximal to the passage 26 of the needle tip 20, e.g., asshown in FIG. 2, and a proximal positon, wherein the distal end 34 isdisplaced a minimum distance from the passage 26, e.g., as shown in FIG.3.

In the embodiment shown in FIG. 1, the handle 50 includes a port 52 acommunicating with the lumen 18 through which the proximal end 32 of theinner member 30 is slidably disposed. In an exemplary embodiment, theport 52 a may include one or more seals, e.g., hemostatic seal, toprovide a fluid-tight seal around the inner member 30 and prevent fluidwithin the lumen 18 from escaping out the port 52 a. In this embodiment,a hub or handle 38 may be provided on the proximal end 32 of the innermember 30 to facilitate manipulation of the inner member between thedistal and proximal positions.

Optionally, one or more stops (not shown) may be provided within thehandle 50 and/or on the proximal end 32 to limit movement of the innermember 30 between the distal and proximal positions. Alternatively, theinner member 30 may be removable entirely from and insertable into theouter member 20 via the port 52 a. In a further alternative, theproximal end 32 of the inner member 30 may be disposed within the handle50 and coupled to an actuator 54 (shown in phantom in FIG. 1), e.g., aslider, dial, and the like, that may be manipulated to move the innermember 30 between the distal and proximal positions. In anotheralternative, a biasing mechanism, e.g., a spring, ratchet, and/or otherdevice (not shown) may be provided in the handle 50 that may selectivelybias the inner member 30 to one or both of the distal and proximalpositions during use, as described elsewhere herein.

As shown in FIG. 2, in the distal position, the distal end 34 of theinner member 30 may be spaced apart a predetermined distance from theentrance to the passage 26, e.g., between about one and fiftymillimeters (1.0-50 mm), such that injectate passing through the lumen18 may easily enter the passage 26 with minimal additional resistance.Alternatively, the distal end 34 of the inner member 30 may be smallerthan the passage 26 such that the distal end 34 may be at leastpartially received within the passage 26 in the distal position (notshown). In the proximal position shown in FIG. 3, the distal end 34 maybe retracted a predetermined distance, e.g., between about ten and fivehundred millimeters (10-500 mm), sufficient to prevent undesiredexpression of the injectate from the needle tip 20 after an injection,as described elsewhere herein.

With continued reference to FIG. 1, the handle 50 may also include aside port 52 b also communicating with the lumen 18, which may becoupled to the source of injectate 60. Optionally, the side port 52 bmay include one or more connectors, e.g., a Luer fitting and the like(not shown), such that the source of injectate 60 may be removablycoupled to the side port 52 b. Alternatively, a manifold (not shown) maybe provided on the proximal end 12 of the outer shaft 10, e.g.,integrated into the handle 50, to contain and/or deliver the injectate,e.g., as disclosed in U.S. Publication No. 2017/0119956.

In an exemplary embodiment, the source 60 may be a syringe 62 includinga barrel 64 containing injectate 65, e.g., connected to the side port 52b by tubing 63, and a piston 66 on a distal end of a plunger 68 slidablydisposed within the barrel 64 that may be depressed to deliver theinjectate 65 through the tubing 66 and side port 52 b into the lumen 18.Alternatively, other actuators may be provided, if desired. For example,for viscous materials, a screw actuator (not shown) may be provided toadvance the piston 66, which may be provide a mechanical advantage thandirectly manipulating the piston 66 using the plunger 68, or a motorizedpump or other driver (not shown) may be provided.

With further reference to FIG. 1, the device 8 may include a component(e.g., an auxiliary tube, passage, or lumen, not shown) configured todeliver a relatively low viscosity fluid to the distal end of the lumen18, e.g., for the purpose of reducing or eliminating the inflow ofmaterial (e.g., blood) into the passage 26 as a result of volumedisplacement within the lumen 18. Flow of fluid through the componentmay be controlled, e.g., according to flow and/or pressure, e.g., inorder achieve adequate pressure release within the lumen 18.Alternatively, or in addition, the device 8 may include a mechanism (notshown) for temporarily occluding the passage 26 or intermittentlyflushing the passage 26, e.g., to prevent inflow of blood into thepassage 26 during the release of pressure within the lumen 18 and/or toeliminate blood from the passage 26 after relative pressure equilibriumhas been achieved.

During use, the injection device 8 may be used to deliver injectate intoa patient's body, e.g., into tissue within the wall of the heart,adjacent vessels of a patient's vasculature, and the like. For example,the distal end 14 may be introduced into a patient's body, e.g., into achamber of the patient's heart (not shown), via one or more accesssheaths, guidewires, and the like, and positioned as desired.Optionally, the distal end 14 and needle tip 20 may be positioned and/orotherwise oriented towards a target injection site using externalimaging, e.g., fluoroscopy and the like, using one or more markers onthe distal end 14 and/or needle tip 20. Optionally, contrast materialmay be delivered via the device 8 to facilitate such imaging and/orpositioning, e.g., via the lumen 18 or, alternatively, via a secondarylumen.

Once positioned, the device 8 may be advanced to inserting the needletip 20 into tissue at the target injection site. Under visualization,the needle tip 20 may be inserted a desired depth and/or a substantiallyflat distal surface of the distal end 14 (or distal stop) surroundingthe needle tip 20 may contact a wall of the body lumen to limitpenetration of the needle tip 20 into the tissue.

With the pressure release member 30 in the distal position, i.e., withthe distal end 34 disposed adjacent the passage 26 as shown in FIG. 2,injectate may be delivered from the source 60 through the lumen 18around the pressure release member 30 into the passage 26 and out theoutlet 27 into the tissue. As described elsewhere herein, with viscousmaterials, substantial pressure may be required to deliver the injectatethrough the lumen 18 and passage 26 into the tissue.

After delivering the injectate, the pressure release member 30 may bewithdrawn proximally such that the distal end 34 moves proximally awayfrom the passage 26, as shown in FIG. 3, to prevent injectate fromexpressing out the needle tip 20. For example, the action of withdrawingthe distal end 34 may create additional available space within the lumen18 adjacent the passage 26 to absorb and/or relieve residual pressure,e.g. due to the compressibility of the injectate and/or system. Inaddition, surface tension between the distal end 34 and the surroundingresidual injectate and/or the viscosity of the injectate may pull orotherwise remove some of the injectate proximally away from the passage26, thereby minimizing the risk that injectate leaks or escapes from theoutlet 27.

For example, in one method, the hub 38 on the proximal end 32 of theinner member 30 may be pulled manually relative to the handle 50 towithdraw the inner member to the proximal position. Alternatively, theinner member 30 may be coupled to an actuator 54, which may be used towithdraw the inner member 30. Once withdrawn, the needle tip 20 may beremoved from the tissue and the device 8 may be withdrawn from thepatient's body or alternatively, the distal end 14 may be directed toanother location where another injection is desired. In thisalternative, once the needle tip 20 is positioned and inserted into thenext target injection site, the inner member 30 may be advanced back tothe distal position before delivering the injectate (since any residualinjectate that escapes during advancement of the inner member 30 willsimply be delivered into the target tissue).

Alternatively, a biasing mechanism may be coupled to the inner member 30such that the inner member 30 is automatically withdrawn from the distalposition to the proximal position after delivering the injectate. Forexample, pressure from delivery of the injectate may activate thebiasing mechanism such that, upon removal of the pressure after theinjection, the biasing mechanism may automatically direct the innermember 30 to the proximal position. If an additional injection isdesired, the biasing mechanism may be reset, e.g., after inserting theneedle tip 20 into another target injection site, to advance the innermember 20 back to the distal position before delivery. In a furtheralternative, the biasing mechanism may bias the inner member 30 to theproximal position and pressure or actuation during delivery of theinjectate may advance the inner member 30 temporarily to the distalposition until the injection is complete.

Although particularly useful for performing injections within a chamberof a heart, the needle devices and systems described herein may be usedto perform other procedures, e.g., elsewhere within a patient'scardiovascular system or other locations within a patient's body, suchas the lungs, liver, gastrointestinal tract, etc.

The foregoing disclosure of the exemplary embodiments has been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Many variations and modifications of the embodiments described hereinwill be apparent to one of ordinary skill in the art in light of theabove disclosure.

Further, in describing representative embodiments, the specification mayhave presented the method and/or process as a particular sequence ofsteps. However, to the extent that the method or process does not relyon the particular order of steps set forth herein, the method or processshould not be limited to the particular sequence of steps described. Asone of ordinary skill in the art would appreciate, other sequences ofsteps may be possible. Therefore, the particular order of the steps setforth in the specification should not be construed as limitations on theclaims.

While the invention is susceptible to various modifications, andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that the invention is not to be limited to the particular formsor methods disclosed, but to the contrary, the invention is to cover allmodifications, equivalents and alternatives falling within the scope ofthe appended claims.

1. A device for injecting a viscous injectate into tissue within apatient's body, comprising: an outer member comprising a proximal end, adistal end sized for introduction into a patient's body, and a lumenextending between the proximal and distal ends; a needle tip extendingdistally beyond the distal end to a distal tip and including a passagecommunicating between the lumen and an outlet in the distal tip; ahandle on the proximal end including a port communicating with the lumenand connectable to a source of viscous injectate for delivering theinjectate through the port, lumen, and passage and out the outlet; andan inner member slidably disposed within the lumen, the inner membercomprising a proximal end disposed adjacent the outer member proximalend and a distal end disposed within the lumen, the inner member havingan outer profile smaller than inner profile of the lumen such that theinjectate passes through the lumen around the inner member, the innermember movable from a distal position wherein the inner member distalend is disposed adjacent the passage during delivery of the injectateand a proximal position in which the inner member distal end is directedproximally away from the passage after delivery of the injectate toprevent the injectate from expressing from the distal tip.
 2. The deviceof claim 1, wherein the needle tip has a cross-section smaller than thedistal end.
 3. The device of claim 1, further comprising a distal stopon the outer member distal end, the needle tip extending distally beyondthe distal stop.
 4. The device of claim 3, wherein the distal stopcomprises one or more passages communicating between the lumen and theneedle tip passage.
 5. The device of claim 3, wherein the distal stopcomprises a body having an outer dimension larger than an outerdimension of the outer member distal end.
 6. The device of claim 3,wherein the distal stop comprises a rounded or flat distal surfaceadjacent the needle tip to limit penetration of the needle tip intotissue.
 7. The device of claim 1, further comprising a release memberport on the handle through which the inner member is slidably disposedsuch that the inner member proximal end is exposed from the handle andmay be manipulated manually to move the inner member between the distalposition and the proximal position.
 8. The device of claim 7, furthercomprising one or more seals in the port to provide a fluid-tight sealand prevent fluid within the lumen from escaping out the port.
 9. Thedevice of claim 7, further comprising a hub on the inner member proximalend to facilitate manipulating the inner member.
 10. The device of claim1, further comprising an actuator on the handle coupled to the innermember for directing the inner member between the distal position andthe proximal position.
 11. A system for injecting a viscous injectateinto tissue within a patient's body, comprising: an outer membercomprising a proximal end, a distal end sized for introduction into apatient's body, and a lumen extending between the proximal and distalends; a needle tip extending distally beyond the distal end to a distaltip, the needle tip having a cross-section smaller than the distal endand a passage communicating between the lumen and an outlet in thedistal tip; a source of viscous injectate coupled to the proximal endand communicating with the lumen for delivering the injectate throughthe lumen and passage and out the outlet; and an inner member slidablydisposed within the lumen, the inner member comprising a proximal enddisposed adjacent the outer member proximal end and a distal enddisposed within the lumen, the inner member having an outer profilesmaller than inner profile of the lumen such that the injectate passesthrough the lumen around the inner member, the inner member movable froma distal position wherein the inner member distal end is disposedadjacent the passage during delivery of the injectate and a proximalposition in which the inner member distal end is directed proximallyaway from the passage after delivery of the injectate to prevent theinjectate from expressing from the distal tip.
 12. The system of claim11, wherein the source of viscous injectate comprises a manifold coupledto the outer member proximal end comprising an actuator for selectivelydirecting the injectate from the source through the lumen and out theoutlet.
 13. The system of claim 11, further comprising: a handle on theouter member proximal end; and a port on the handle through which theinner member proximal end is slidably disposed such that the innermember proximal end is exposed from the handle and may be manipulatedmanually to move the inner member between the distal position and theproximal position.
 14. The system of claim 13, further comprising one ormore seals in the port to provide a fluid-tight seal and prevent fluidwithin the lumen from escaping out the port.
 15. The system of claim 13,further comprising a hub on the inner member proximal end to facilitatemanipulating the inner member.
 16. The system of claim 11, furthercomprising: a handle on the outer member proximal end; and an actuatoron the handle coupled to the inner member for directing the inner memberbetween the distal position and the proximal position.
 17. The system ofclaim 11, further comprising: an actuator for delivering the injectatefrom the source into the lumen, the actuator coupled to the inner memberfor advancing the inner member to the distal position during delivery ofthe injectate; and a biasing mechanism coupled to the inner member forautomatically retracting the inner member to the proximal position whenthe actuator is released to discontinue delivery of the injectate. 18.The system of claim 11, further comprising a distal stop on the outermember distal end, the needle tip extending distally beyond the distalstop.
 19. The system of claim 18, wherein the distal stop comprises oneor more passages communicating between the lumen and the needle tippassage. 20-22. (canceled)
 23. A method for delivering viscous injectateinto tissue within a patient's body using an injection device comprisingan outer member including a proximal end, a distal end, and a lumenextending therebetween, a needle tip extending from the distal end, anda pressure release member slidably disposed within the lumen, the methodcomprising: introducing the distal end of the elongate member into abody lumen adjacent a target injection site; inserting the needle tipinto tissue at the target injection site; with a distal end of thepressure release member disposed adjacent the needle tip within thelumen, delivering injectate from a source through the lumen around thepressure release member and through the needle tip into the tissue; andafter delivering the injectate, withdrawing the pressure release memberproximally such that the pressure release member distal end movesproximally away from the passage to prevent injectate from expressingout the needle tip. 24-28. (canceled)